Hitherto, polymer particles employed for many applications have been generally produced by emulsion polymerization, seed-emulsion polymerization or suspension polymerization. In emulsion polymerization, a particle size of the obtained polymer particles is of a submicron meter meter order. This does not meet the requirements of obtaining large particle sizes. In seed-emulsion polymerization, several steps are required to obtain a large particle size. This is a disadvantage in production cost and workability. In suspension polymerization, the obtained particles have a broad particle size distribution, which is not preferred for certain usages.
For improving the above defects, one or more vinyl monomers which are soluble in a hydrophilic organic solvent are polymerized in a solution of said hydrophilic organic solvent and a polymeric dispersant, to obtain a polymer which is not dissolved or swelled with the organic solvent (Japanese Patent Publication (unexamined) Nos. 18966.1986 and 228458/1986). The polymer particles thus obtained have a quite narrow particle size distribution, but which are still insufficient in certain utilities.